This invention relates to a modem and, in particular, a modem for allowing communications with a host using either an RS-232 or a Universal Serial Bus (USB) interface.
Modems allow a host, such as a computer, to transfer data over telephone networks. Typically, the data is transferred to another modem over Plain Old Telephone System (POTS) lines. The receiving modem then transfers the data to another host. Modems connect to a POTS line through an RJ11 jack.
Typically modems connect to a host computer through an RS-232 serial port. As the demands for more connectivity to host computers has grown, the demand for a more versatile connection to a host has also grown. Thus, computers are providing Universal Serial Bus (USB) connections. The USB connections operate pursuant to the USB specification, currently version 1.0. Additional specifications may be used, such as the USB Class Definition for Communication Devices (CDC) or non-USB specifications. As computers or hosts with USB interfaces are created, modems providing USB interfaces may be desired. However, many computers continue to use RS-232 interfaces for modem connections. Thus, a different modem may need to be purchased depending on the type of interface on the host computer.